JP4993236B2 - Positive photoresist composition - Google Patents

Description

  The present invention relates to a positive photoresist composition excellent in developability and heat resistance.

  As a resist used in the manufacture of semiconductors such as IC and LSI, the manufacture of display devices such as LCD, and the manufacture of printing original plates, there is a positive photoresist using a photosensitizer such as an alkali-soluble resin and a 1,2-naphthoquinonediazide compound. Are known. As the alkali-soluble resin, a positive photoresist composition using a cresol novolak resin made of m-cresol and p-cresol as a raw material has been proposed (for example, see Patent Document 1).

  Further, as the alkali-soluble resin, a positive photoresist composition using a cresol novolac resin made of m-cresol, p-cresol and resorcinol as a raw material has been proposed (see, for example, Patent Document 2). ).

  The positive photoresist compositions described in Patent Documents 1 and 2 have been developed for the purpose of improving developability such as sensitivity, but in recent years, the integration of semiconductors has increased and the pattern tends to become thinner. Therefore, more excellent sensitivity has been demanded. However, the positive photoresist composition described in Patent Document 1 has a problem that sufficient sensitivity corresponding to thinning cannot be obtained. Furthermore, since various heat treatments are performed in the manufacturing process of semiconductors and the like, higher heat resistance is also demanded. However, the positive photoresist composition described in Patent Document 1 has a problem that it is not sufficiently heat resistant. there were.

  Here, in order to improve the sensitivity of the novolak-type phenolic resin that is an alkali-soluble resin, there is a problem that the heat resistance is reduced when the design is to improve alkali solubility, and the sensitivity is reduced when the design is to improve the heat resistance, It is difficult to achieve both sensitivity and heat resistance, and a material having both sensitivity and heat resistance is required.

Japanese Patent Application Laid-Open No. 60-159846 JP 11-258808 A

  The problem to be solved by the present invention is to provide a positive-type photoresist composition that achieves a high level of sensitivity and heat resistance, both of which have been difficult to achieve together.

  As a result of intensive research, the present inventors have used a cresol novolac resin produced using m-cresol, p-cresol and formaldehyde as essential raw materials as an alkali-soluble resin, and a novolak type produced using o-cresol as an essential raw material. The present inventors have found that a positive photoresist composition using a novolac type phenol resin obtained by modifying a phenol resin with resorcinol as a sensitivity improver has excellent sensitivity and heat resistance, and has completed the present invention.

  That is, the present invention relates to a cresol novolak resin (A) produced using m-cresol, p-cresol and formaldehyde as essential raw materials, and a novolac type phenol resin (B) produced using o-cresol, resorcinol and formaldehyde as essential raw materials. And a positive photoresist composition.

  The positive photoresist composition of the present invention has both high sensitivity and heat resistance that have been difficult to achieve at the same time, and has a very high sensitivity and heat resistance. Can be suitably used as a positive photoresist used in the manufacture of semiconductors such as IC and LSI, the manufacture of display devices such as LCDs, and the manufacture of printing original plates.

  The positive photoresist composition of the present invention includes a cresol novolak resin (A) produced using m-cresol, p-cresol and formaldehyde as essential raw materials, and a novolak produced using o-cresol, resorcinol and formaldehyde as essential raw materials. Type phenol resin (B).

  First, the cresol novolac resin (A) will be described. The cresol novolac resin (A) is a novolak type phenol resin obtained by condensing m-cresol, p-cresol and formaldehyde as essential raw materials.

  Since the molar ratio [m-cresol / p-cresol] of m-cresol and p-cresol used as an essential raw material of the cresol novolak resin (A) can achieve both sensitivity and heat resistance, 10/0 to 2/8 Is preferable, and the range of 7/3 to 2/8 is more preferable.

  You may use together phenolic compounds other than m-cresol and p-cresol used as an essential raw material of the said cresol novolak resin (A) as a raw material. Examples of such phenol compounds include phenol; o-cresol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5- Xylenol such as xylenol; ethylphenol such as o-ethylphenol, m-ethylphenol and p-ethylphenol; butylphenol such as isopropylphenol, butylphenol and pt-butylphenol; p-pentylphenol, p-octylphenol and p-nonylphenol Alkylphenols such as p-cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol and iodophenol; p-phenylphenol, aminophenol, nitrophenol, 1-substituted phenols such as nitrophenol and trinitrophenol; condensed polycyclic phenols such as 1-naphthol and 2-naphthol; resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol And polyhydric phenols such as F, bisphenol S, and dihydroxynaphthalene. These other phenol compounds can be used alone or in combination of two or more. Moreover, when using together another phenol compound, it is preferable to set the usage-amount to the range of 0.05-1 mol with respect to a total of 1 mol of m-cresol and p-cresol.

  Moreover, you may use together aldehyde compounds other than formaldehyde used as an essential raw material of the said cresol novolak resin (A) as a raw material. Examples of such aldehyde compounds include paraformaldehyde, 1,3,5-trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allyl. Examples include aldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, and salicylaldehyde. These aldehyde compounds can be used alone or in combination of two or more. Moreover, it is preferable to use formaldehyde as a raw material of the said cresol novolak resin (A), and you may use formaldehyde and another aldehyde compound together. When formaldehyde and another aldehyde compound are used in combination, the amount of the other aldehyde compound used is preferably in the range of 0.05 to 1 mol with respect to 1 mol of formaldehyde.

  The condensation reaction of the phenol compound containing m-cresol and p-cresol and the aldehyde compound containing formaldehyde in producing the cresol novolak resin (A) is preferably performed in the presence of an acid catalyst. Examples of the acid catalyst include oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, paratoluenesulfonic acid, zinc acetate, manganese acetate, and the like. These acid catalysts can be used alone or in combination of two or more. Of these acid catalysts, oxalic acid is preferable because it does not decompose and remain by heating. The acid catalyst may be added before the reaction or during the reaction.

  In addition, the molar ratio [(F) / (P)] of the phenol compound (P) and the aldehyde compound (F) in producing the cresol novolak resin (A) can provide excellent sensitivity and heat resistance. Therefore, the range of 0.3 to 1.6 is preferable, and the range of 0.5 to 1.3 is more preferable.

  As a more specific production method of the novolak type phenol resin (A), a phenol compound, an aldehyde compound and an acid catalyst are heated to 60 to 140 ° C. to advance a polycondensation reaction, and then dehydrated under reduced pressure conditions. The method of making a monomer removal is mentioned.

  Next, the novolac type phenol resin (B) will be described. The novolac-type phenol resin (B) is obtained by condensing o-cresol, resorcinol and formaldehyde as essential raw materials.

  The phenol compound used as a raw material for the novolak type phenol resin (B) is o-cresol, but other phenol compounds may be used in combination. Examples of such phenol compounds include phenol; o-cresol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5- Xylenol such as xylenol; ethylphenol such as o-ethylphenol, m-ethylphenol and p-ethylphenol; butylphenol such as isopropylphenol, butylphenol and pt-butylphenol; p-pentylphenol, p-octylphenol and p-nonylphenol Alkylphenols such as p-cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol and iodophenol; p-phenylphenol, aminophenol, nitrophenol, 1-substituted phenols such as nitrophenol and trinitrophenol; condensed polycyclic phenols such as 1-naphthol and 2-naphthol; resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol And polyhydric phenols such as F, bisphenol S, and dihydroxynaphthalene. These other phenol compounds can be used alone or in combination of two or more. Moreover, when using together another phenol compound, it is preferable that the usage-amount is set to the range of 0.05-1 mol with respect to a total of 1 mol of o-cresol.

  Moreover, although the aldehyde compound used as the raw material of the novolak type phenol resin (B) is formaldehyde, other aldehyde compounds may be used in combination. Examples of such aldehydes include paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, Examples include acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, and salicylaldehyde. These aldehyde compounds can be used alone or in combination of two or more. Moreover, when using another aldehyde compound together, it is preferable to make the usage-amount of another aldehyde compound into the range of 0.05-1 mol with respect to 1 mol of formaldehyde.

  The number of moles of resorcinol relative to 1 mole of o-cresol, which is a raw material of the novolak-type phenol resin (B), is preferably in the range of 0.1 to 0.7 mole, since both sensitivity and heat resistance can be achieved. A range of 0.5 mol is more preferred.

  Moreover, when manufacturing the said novolak-type phenol resin (B), the total number of moles of phenol compound (P) which added o-cresol and resorcinol, and other phenol compounds as needed, formaldehyde, and it Accordingly, the molar ratio [(F) / (P)] with respect to the total number of moles of the aldehyde compound (F) to which other aldehydes have been added can provide excellent sensitivity and heat resistance. The range of 6 is preferable, and the range of 0.5 to 1.3 is more preferable.

  The novolac type phenol resin (B) is preferably produced by one of the following two production methods because the raw materials o-cresol and resorcinol have different reactivity with formaldehyde.

(Production method 1: Two-step reaction of novolak formation)
A production method in which o-cresol and other phenol compounds and formaldehyde and other aldehyde compounds are first novolaked by a condensation reaction in the presence of an acid catalyst, and then resorcinol is added to further novolak.

(Production method 2: Two-stage reaction of resorification and novolakization)
A production method comprising the following step 1 (resolation step), step 2 (neutralization / catalyst removal step) and step 3 (novolacization step).

(Process 1)
o-Cresol and other phenol compounds and formaldehyde and other aldehyde compounds are heated to 40 to 140 ° C. in the presence of an alkaline catalyst to cause a condensation reaction to obtain a resol type phenol resin (B ′).

(Process 2)
The novolak type phenol resin (B ′) obtained in Step 1 is neutralized with an acid, and the separated water is extracted. Then, water is added and the separated aqueous layer is similarly extracted to remove the catalyst.

(Process 3)
Resorcinol, formaldehyde and other aldehyde compounds, and an acid catalyst are added to the novolak-type phenol resin (B ′) from which the acid catalyst has been removed in step 2, and the condensation reaction proceeds by heating to 60 to 140 ° C. Further dehydration and demonomerization are performed under the conditions to obtain a resorcinol-modified novolac type phenol resin (B).

  Examples of the alkaline catalyst used in the production step 1 include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkaline earth metal oxides such as calcium, magnesium, and barium; and hydroxides. Products; primary amines such as ammonia and monoethanolamine; secondary amines such as diethanolamine; tertiary amines such as trimethylamine, triethylamine, triethanolamine, diazabicycloundecene; sodium carbonate, hexamethylenetetramine, etc. Examples include alkaline substances. These alkaline catalysts can be used alone or in combination of two or more. Of these alkaline catalysts, sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide are preferred because of their excellent catalytic activity. The alkaline catalyst may be added before the reaction in the production process 1 or during the reaction.

  Examples of the acid used for neutralization in the production step 2 include sulfuric acid, oxalic acid, and hydrochloric acid. These acids can be used alone or in combination of two or more.

  Examples of the acid catalyst used in the production step 3 include oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, paratoluenesulfonic acid, zinc acetate, manganese acetate, and the like. These acid catalysts can be used alone or in combination of two or more. Of these acid catalysts, oxalic acid is preferred because it is thermally decomposed and does not remain. The acid catalyst may be added before the reaction in the production step 3 or may be added during the reaction.

  Among the two production methods of the above-mentioned novolak type phenol resin (B), production method 2 is preferable because o-cresol and resorcinol can be more uniformly present in the novolak type phenol resin.

  The weight average molecular weight of the cresol novolak resin (A) obtained by the above production method is preferably in the range of 2,000 to 35,000, and more preferably in the range of 5,000 to 20,000. Moreover, the range of the weight average molecular weight of the said novolak-type phenol resin (B) obtained by said manufacturing method has the preferable range of 500-4,000, and the range of 700-2,500 is more preferable. In addition, these weight average molecular weights are measured on the following measurement conditions using gel permeation chromatography (GPC).

[GPC measurement conditions]
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: “Shodex KF802” manufactured by Showa Denko KK (8.0 mm （× 300 mm)
+ Showa Denko “Shodex KF802” (8.0 mmФ × 300 mm)
+ Showa Denko Co., Ltd. “Shodex KF803” (8.0 mmФ × 300 mm)
+ Showa Denko Co., Ltd. “Shodex KF804” (8.0 mmФ × 300 mm)
Column temperature: 40 ° C
Detector: RI (differential refractometer)
Data processing: “GPC-8020 Model II version 4.30” manufactured by Tosoh Corporation
Developing solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample: 0.5% by mass tetrahydrofuran solution in terms of resin solid content filtered through a microfilter Injection amount: 0.1 mL
Standard sample: Monodispersed polystyrene below

(Standard sample: monodisperse polystyrene)
“A-500” manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
“F-1” manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
“F-4” manufactured by Tosoh Corporation
“F-10” manufactured by Tosoh Corporation
“F-20” manufactured by Tosoh Corporation

  The positive photoresist composition of the present invention contains the cresol novolac resin (A) and the novolac type phenol resin (B) described above, and the blending amount of these is excellent in sensitivity and heat resistance. Therefore, it is preferable to contain the novolac type phenol resin (B) in the range of 3 to 60 parts by mass, and in the range of 5 to 30 parts by mass with respect to 100 parts by mass of the cresol novolac resin (A). It is more preferable.

  The positive photoresist composition of the present invention usually contains a photosensitizer (C) and a solvent (D) in addition to the cresol novolac resin (A) and the novolac phenol resin (B).

  As the photosensitizer (C), a compound having a quinonediazide group can be used. Examples of the compound having a quinonediazide group include 2,3,4-trihydroxybenzophenone, 2,4,4′-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxy. Benzophenone, 2,3,4-trihydroxy-2′-methylbenzophenone, 2,3,4,4′-tetrahydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,3 ′, 4 , 4 ′, 6-pentahydroxybenzophenone, 2,2 ′, 3,4,4′-pentahydroxybenzophenone, 2,2 ′, 3,4,5-pentahydroxybenzophenone, 2,3 ′, 4,4 ′ , 5 ′, 6-hexahydroxybenzophenone, 2,3,3 ′, 4,4 ′, 5′-hexahydroxybenzophenone and the like. Nzophenone compounds; bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (2 ′, 4′-dihydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-tri Hydroxyphenyl) propane, 4,4 ′-{1- [4- [2- (4-hydroxyphenyl) -2-propyl] phenyl] ethylidene} bisphenol, 3,3′-dimethyl- {1- [4- [ Bis [(poly) hydroxyphenyl] alkane compounds such as 2- (3-methyl-4-hydroxyphenyl) -2-propyl] phenyl] ethylidene} bisphenol; -Hydroxyphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4- Hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl)- Tris (hydroxyphenyl) methanes such as 3,4-dihydroxyphenylmethane and bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane or methyl-substituted products thereof; bis (3-cyclohexyl- 4-hydroxyphenyl) -3-hydroxyphenylmethane, bi (3-cyclohexyl-4-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) ) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenyl Methane, bis (3-cyclohexyl-2-hydroxyphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4- Hydroxy-3- Tilphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4) -Methylphenyl) -4-hydroxyphenylmethane and the like, bis (cyclohexylhydroxyphenyl) (hydroxyphenyl) methanes or methyl-substituted products thereof, and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2 Diazide-4-sulfonic acid, complete ester compounds of the sulfonic acid having a quinonediazide group such as o-anthraquinone diazide sulfonic acid, partial ester compound, an amide compound or partially amidated product thereof. These photosensitizers can be used alone or in combination of two or more.

  Since the compounding amount of the photosensitizer (C) in the positive photoresist composition of the present invention provides good sensitivity and a desired pattern, the cresol novolac resin (A) and the novolac phenol resin The range of 3-50 mass parts is preferable with respect to the total of 100 mass parts of (B), and the range of 5-30 mass parts is more preferable.

  Examples of the solvent (D) include ethylene glycol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, Diethylene glycol dialkyl ethers such as diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate Propylene glycol alkyl ether acetates such as Tate; Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl amyl ketone; Cyclic ethers such as dioxane; Methyl 2-hydroxypropionate, Ethyl 2-hydroxypropionate, 2-hydroxy-2-methyl Ethyl propionate, ethyl ethoxy acetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, methyl acetoacetate And esters such as ethyl acetoacetate. These solvents can be used alone or in combination of two or more.

  The blending amount of the solvent (D) in the positive photoresist composition of the present invention is such that a uniform coating film can be obtained by applying a fluidity of the composition by a coating method such as a spin coating method. It is preferable that the concentration is 30 to 65% by mass.

  The positive photoresist composition of the present invention includes the cresol novolak resin (A), novolac phenol resin (B), photosensitizer (C) and solvent (D), as long as the effects of the present invention are not impaired. Various additives may be blended. Examples of such additives include surfactants such as fillers, pigments, and leveling agents, adhesion improvers, and dissolution accelerators.

  The positive photoresist composition of the present invention comprises the cresol novolak resin (A), novolac phenol resin (B), photosensitizer (C) and solvent (D), and various additives added as necessary. Can be prepared by stirring and mixing to obtain a uniform solution.

  In addition, when a solid material such as a filler or a pigment is blended in the positive photoresist composition of the present invention, it is preferably dispersed and mixed using a dispersing device such as a dissolver, a homogenizer, or a three roll mill. Further, in order to remove coarse particles and impurities, the composition can be filtered using a mesh filter, a membrane filter or the like.

  When the positive photoresist composition of the present invention is exposed through a mask, the resin composition undergoes a structural change in the exposed area, and the solubility in an alkali developer is promoted. On the other hand, in the non-exposed area, low solubility in an alkali developer is maintained, and this difference in solubility enables patterning by alkali development and can be used as a resist material.

  Examples of the light source for exposing the positive photoresist composition of the present invention include infrared light, visible light, ultraviolet light, far ultraviolet light, X-rays, and electron beams. Among these light sources, ultraviolet light is preferable, and G-line (436 nm) and I-line (365 nm) are preferable.

  Examples of the alkali developer used for development after exposure include inorganic alkaline substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; ethylamine, n-propylamine, and the like. Secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxy Alkaline aqueous solutions such as quaternary ammonium salts such as pyrrole and cyclic amines such as pyrrole and pihelidine can be used. In these alkaline developers, alcohols, surfactants and the like can be appropriately added and used as necessary. The alkali concentration of the alkali developer is usually preferably in the range of 2 to 5% by mass, and a 2.38% by mass tetramethylammonium hydroxide aqueous solution is generally used.

  Hereinafter, the present invention will be described in more detail with specific examples. The weight average molecular weight (Mw) of the synthesized resin was measured under the following GPC measurement conditions.

[GPC measurement conditions]
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: “Shodex KF802” manufactured by Showa Denko KK (8.0 mm （× 300 mm)
+ Showa Denko “Shodex KF802” (8.0 mmФ × 300 mm)
+ Showa Denko Co., Ltd. “Shodex KF803” (8.0 mmФ × 300 mm)
+ Showa Denko Co., Ltd. “Shodex KF804” (8.0 mmФ × 300 mm)
Column temperature: 40 ° C
Detector: RI (differential refractometer)
Data processing: “GPC-8020 Model II version 4.30” manufactured by Tosoh Corporation
Developing solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample: 0.5% by mass tetrahydrofuran solution in terms of resin solid content filtered through a microfilter Injection amount: 0.1 mL
Standard sample: Monodispersed polystyrene below

(Standard sample: monodisperse polystyrene)
“A-500” manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
“F-1” manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
“F-4” manufactured by Tosoh Corporation
“F-10” manufactured by Tosoh Corporation
“F-20” manufactured by Tosoh Corporation

(Synthesis Example 1)
After adding 648 g of m-cresol, 432 g of p-cresol, 2.5 g of oxalic acid and 492 g of a 42% by weight formaldehyde aqueous solution to a four-necked flask equipped with a stirrer and a thermometer, the temperature was raised to 100 ° C. and reacted for 3 hours. I let you. Subsequently, the temperature was raised to 200 ° C. and the pressure was reduced to dehydrate and remove the monomer, and a solid cresol novolak resin (A1) having a softening point of 145 ° C. and a weight average molecular weight (Mw) of 9,600 was obtained.

(Synthesis Example 2)
To a four-necked flask equipped with a stirrer and a thermometer, m-cresol 432 g, p-cresol 648 g, oxalic acid 2.5 g and 42 mass% formaldehyde aqueous solution 506 g were added, and the temperature was raised to 100 ° C. and reacted for 3 hours. I let you. Next, the temperature was raised to 200 ° C. and the pressure was reduced to dehydrate and remove the monomer, and a solid cresol novolak resin (A2) having a softening point of 150 ° C. and a weight average molecular weight (Mw) of 10,500 was obtained.

(Synthesis Example 3)
After adding 780 g of m-cresol, 1,560 g of p-cresol, 260 g of resorcinol, 10.8 g of oxalic acid, and 1,070 g of a 42% by weight formaldehyde aqueous solution to a four-necked flask equipped with a stirrer and a thermometer, the temperature reaches 100 ° C. The temperature was raised and reacted for 3 hours. Next, the temperature was raised to 200 ° C. and the pressure was reduced to dehydrate and remove the monomer, and a solid cresol novolak resin (A3) having a softening point of 150 ° C. and a weight average molecular weight (Mw) of 9,900 was obtained.

(Synthesis Example 4)
To a four-necked flask equipped with a stirrer and a thermometer, 1,080 g of o-cresol, 54 g of sodium hydroxide and 615 g of a 42% by weight formaldehyde aqueous solution were added, and then the temperature was raised to 60 ° C. and the reaction was continued for 5 hours while stirring. I let you. Next, dilute sulfuric acid was added for neutralization, and the separated water was extracted, and then 375 g of water was added, and the separated aqueous layer was extracted to remove the catalyst.

  Next, after adding 418 g of resorcinol, 2 g of oxalic acid, and 78 g of a 42 mass% formaldehyde aqueous solution, the temperature was raised to 100 ° C. and reacted for 1 hour. Thereafter, the temperature was raised to 170 ° C., and dehydration and demonomer was allowed to proceed for 1 hour. Next, the pressure was reduced and dehydration and demonomerization was performed at 190 ° C. for 2 hours to obtain a solid novolac type phenol resin (B1) having a softening point of 125 ° C. and a weight average molecular weight (Mw) of 1,700.

  Using the cresol novolak resins (A1), (A2), (A3) and the novolac type phenol resin (B1) obtained in Synthesis Examples 1 to 4, a positive photoresist composition was prepared as follows.

Example 1
16 parts by mass of the cresol novolak resin (A1) obtained in Synthesis Example 1, 4 parts by mass of the novolak type phenol resin (B1) obtained in Synthesis Example 4, and a photosensitizer (“P-200” manufactured by Toyo Gosei Co., Ltd.) 5 parts by mass and 75 parts by mass of a solvent (propylene glycol monomethyl acetate; hereinafter abbreviated as “PGMEA”) were uniformly mixed to obtain a positive photoresist composition (1).

(Example 2)
In place of the cresol novolak resin (A1) used in Example 1, the same procedure as in Example 1 was used except that the novolak type phenol resin (A2) obtained in Synthesis Example 2 was used. 2) was obtained.

(Comparative Example 1)
16 parts by weight of the novolak type phenol resin (A1) obtained in Synthesis Example 1, 5 parts by weight of a photosensitizer (“P-200” manufactured by Toyo Gosei Co., Ltd.) and 75 parts by weight of PGMEA are uniformly mixed to obtain a positive type photo A resist composition (3) was obtained.

(Comparative Example 2)
In place of the cresol novolak resin (A1) used in Comparative Example 1, the same procedure as in Comparative Example 1 was conducted except that the novolak type phenol resin (A2) obtained in Synthesis Example 2 was used. 4) was obtained.

(Comparative Example 3)
In place of the cresol novolak resin (A1) used in Comparative Example 1, the same procedure as in Comparative Example 1 was conducted except that the novolac type phenol resin (A3) obtained in Synthesis Example 3 was used. 5) was obtained.

[Measurement of alkali dissolution rate and evaluation of sensitivity]
A composition in which the positive photoresist compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were not blended with a photosensitive agent was prepared separately to obtain a composition for measuring sensitivity. The composition prepared for sensitivity measurement was applied on a silicon wafer having a diameter of 5 inches using a spin coater and then dried at 110 ° C. for 60 seconds to obtain a thin film having a thickness of 1 μm. It is immersed in an alkaline solution (2.38 mass% tetramethylammonium hydroxide aqueous solution) for 60 seconds, and the film thickness after immersion is measured using a film thickness meter (“F-20” manufactured by Filmetrics) to dissolve the alkali. The speed (ADR) was measured, and the sensitivity was evaluated from the obtained value according to the following criteria.
A: The alkali dissolution rate is 20 nm / second or more.
B: The alkali dissolution rate is 10 nm / second or more and less than 20 nm / second.
C: The alkali dissolution rate is less than 10 nm / second.

[Thermogravimetry and heat resistance evaluation]
The positive photoresist compositions obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were cured by heating at 130 ° C. for 30 minutes, and then thermogravimetric measurement (TG) was performed to determine the rapid weight. As the inflection point at which the change occurs and the heat resistance temperature, the heat resistance was evaluated according to the following criteria.
A: The heat resistant temperature is 170 ° C. or higher.
B: The heat resistant temperature is 150 ° C. or higher and lower than 170 ° C.
C: The heat resistant temperature is less than 150 ° C.

  Table 1 shows the results of each evaluation using the positive photoresist compositions (1) to (5) obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

  From the evaluation results shown in Table 1, the positive photoresist composition (1) of the present invention obtained in Example 1 has a very fast alkali dissolution rate of 23.7 nm / second and is excellent. It was found to have sensitivity. Moreover, it was found that the heat-resistant temperature was as high as 179 ° C. and excellent in heat resistance.

  In addition, the positive photoresist composition (2) of the present invention obtained in Example 2 is also very rapidly dissolved at 20.2 nm / second in the same manner as the positive photoresist composition (1) of Example 1. It was found to have speed and excellent sensitivity. Moreover, it was found that the heat-resistant temperature was as high as 182 ° C. and excellent in heat resistance.

  On the other hand, the positive photoresist composition (3) of Comparative Example 1 uses a cresol novolak resin made from m-cresol and p-cresol as an alkali-soluble resin, and is an essential component in the positive photoresist composition of the present invention. This positive type photoresist composition (3) has an alkali dissolution rate as slow as 9.6 nm / second and insufficient sensitivity. I understood. Moreover, it was found that the heat resistant temperature was as low as 144 ° C. and the heat resistance was insufficient.

  The positive photoresist composition (4) of Comparative Example 2 is an essential component in the positive photoresist composition of the present invention using a cresol novolac resin made from m-cresol and p-cresol as an alkali-soluble resin. In this example, no novolak type phenol resin (B) was blended, but this positive photoresist composition (4) was found to have a low alkali dissolution rate of 6.5 nm / second and insufficient sensitivity. It was. Moreover, it was found that the heat resistant temperature was as low as 148 ° C. and the heat resistance was insufficient.

  The positive photoresist composition (5) of Comparative Example 3 uses a cresol novolac resin made from m-cresol, p-cresol and resorcinol as an alkali-soluble resin, and is an essential component in the positive photoresist composition of the present invention. This positive photoresist composition (5) has an alkali dissolution rate as slow as 14.4 nm / second and insufficient sensitivity. I understood. Further, it was found that the heat resistant temperature was as low as 151 ° C. and the heat resistance was insufficient.

Claims (5)

  It contains cresol novolak resin (A) produced using m-cresol, p-cresol and formaldehyde as essential raw materials, and novolac type phenol resin (B) produced using o-cresol, resorcinol and formaldehyde as essential raw materials. A positive photoresist composition.   2. The positive photoresist composition according to claim 1, wherein the number of moles of resorcinol is in the range of 0.05 to 1 mole with respect to 1 mole of o-cresol which is a raw material of the novolak type phenol resin (B).   The positive photoresist composition according to claim 1 or 2, wherein the novolak type phenol resin (B) has a weight average molecular weight in the range of 500 to 4,000.   The novolac type phenol resin (B) is obtained by subjecting o-cresol and formaldehyde to a condensation reaction in the presence of an alkaline catalyst to obtain a resol type phenol resin (B ′), and then neutralizing the resin (B ′). The photoresist composition according to any one of claims 1 to 3, which is obtained by adding resorcinol and formaldehyde and performing a condensation reaction in the presence of an acid catalyst.   The positive photoresist according to any one of claims 1 to 4, which contains 3 to 60 parts by mass of the novolac type phenol resin (B) with respect to 100 parts by mass of the novolac type phenol resin (A). Composition.